$A$ man of $60\,kg$ is running on the road and suddenly jumps into a stationary trolley car of mass $120\,kg$. Then,the trolley car starts moving with a velocity of $2\,ms^{-1}$. The velocity of the running man when he jumped into the car was . . . . . . $ms^{-1}$.

$A$ cannon ball is fired with a velocity $200 \, m/s$ at an angle of $60^{\circ}$ with the horizontal. At the highest point of its flight,it explodes into $3$ equal fragments. One fragment goes vertically upwards with a velocity $100 \, m/s$,and the second one falls vertically downwards with a velocity $100 \, m/s$. The third fragment will be moving with a velocity:

$A$ shell is fired from a cannon with a velocity $v$ at an angle $\theta$ with the horizontal direction. At the highest point of its path,it explodes into two pieces of equal masses. One of the pieces retraces its path to the cannon. The speed of the other piece immediately after the explosion is

In the law of conservation of linear momentum,which two physical quantities remain constant,and which physical quantity remains zero?

$A$ bomb of mass $16 \ kg$ at rest explodes into two fragments of masses $4 \ kg$ and $12 \ kg$. The velocity of the $12 \ kg$ fragment is $4 \ m/s$. What is the kinetic energy of the other fragment in $J$?

Newton's third law of motion leads to the law of conservation of